An anti-coal campaigner who sent out a fake ANZ media release causing a $314 million slump in the sharemarket value of Whitehaven Coal is unlikely to spend time in jail.

Jonathan Moylan 26, of Newcastle, pleaded guilty in May to one offence of contravening s1041E of the Corporations Act for disseminating false information to the market.

The maximum penalty is 10 years jail or a fine of up to $765,000, or both however Moylan could be assessed for an intensive correction order, which is similar to home detention.

In the NSW Supreme Court on Friday, Moylan's barrister Robert Sutherland SC said his client had only intended to draw attention to the bank's $1.26 billion loan facility to Whitehaven Coal for its Maules Creek coal project.

Moylan thought the bank's decision to fund what he believed was an environmentally damaging project contradicted with its push to market itself as environmentally friendly, Mr Sutherland said.

"He was seeking to embarrass [ANZ]", Mr Sutherland said.

The court was given a written statement by Moylan in which he apologised to shareholders who lost money when the hoax announcement was picked up by various media organisations and led to a temporary $314 million reduction in Whitehaven Coal's market capitalisation.

He said he was particularly sorry for investors whose retirement savings have been affected by the hoax, saying "they have a right to feel deceived and injured".

Crown Prosecutor David Staehli SC said Moylan must have been "aware of what he was getting into to a point" and that his actions could impact Whitehaven's share price and therefore individual shareholders.

He said Moylan's deception involved "extensive planning and premeditation", including setting up the email address media@anzcorporate.com at a cost of $27, copying the ANZ logo from the bank's website and using the name of a real ANZ communications spokesman in the media release.

Moylan listed his own mobile number and changed his voicemail to the name of the legitimate ANZ employee to continue the deception.

The email was sent on January 7 last year to 295 recipients at 98 media organisations and said the bank had made its decision on "environmental and ethical grounds".

However Mr Staelhi did not press for a custodial sentence, saying "any business journalist worth their salt" should have checked the Australian Stock Exchange's platform for releasing market sensitive information before publishing.

Moylan, who speaks three languages and works as a freelance translator, was supported by NSW Greens MP John Kaye, Greens senator Lee Rhianon and about 100 members of the "standwithjono" campaign.

Campaign coordinator Nicola Paris said the legislation under which Moylan had been charged "was never intended to pursue people acting in good conscience."

"The move to take this matter to the Supreme Court is yet another overreach in this relentless pursuit of a young man acting on principle. This lies in stark contrast with the failure of ASIC to prosecute serious corporate crime whilst people found guilty of insider trading such as John Gay, get a slap on the wrist," she said.

The court heard Whitehaven soon recovered its share price and there was no evidence of financial damage go the ANZ bank.